The project examines the neuroanatomical bases of spatial discrimination and memory. In particular, it tests two hypotheses. First, the hippocampus plays a major role in spatial memory. Second, the hippocampus normally performs this function by integrating cortical and subcortical brain areas through its extrinsic connections. A series of behavioral dissociations will examine the specificity of the hippocampus for spatial function. A series of neuroanatomical dissociations will examine the way in which the hippocampus is functionally integrated with other brain structures. The major experiments test animals with selective damage of particular components of the hippocampal system in tasks that are diagnostic for spatial and nonspatial functions. A line of converging evidence from brain stimulation and single unit recording is also proposed.